The present invention relates to a side airbag apparatus that inflates and deploys an airbag at a side wall portion of a passenger compartment corresponding to a seat in the passenger compartment on which a passenger is seated so as to protect the passenger in a collision of a vehicle.
Conventionally, Japanese Laid-Open Patent Publication No. 2005-47471, for example, discloses one such type of side airbag apparatus. FIGS. 12A and 12B illustrate a typical example of the side airbag apparatus of this publication.
As shown in FIGS. 12A and 12B, a seat 10 in a passenger compartment has a seat cushion 11 on which a passenger is seated and a seat back 12 supporting the back of the passenger. A side airbag apparatus 20 is accommodated in one of the sides of the seat back 12. The side airbag apparatus 20 includes an airbag 22 having a lower portion 22A and an upper portion 22B. If an impact pressure sensor detects pressure caused by an impact on a lateral portion of the vehicle, an inflator injects gas into the airbag 22. This inflates and deploys the airbag 22 at a side wall portion 14 in the passenger compartment corresponding to the seat 10 in order to protect a passenger on the seat 10.
Typically, the dimensions of the airbag 22 in the fully inflated and deployed state, particularly the thickness of the airbag 22 in the fully inflated and deployed state in a lateral direction of the vehicle, are set in accordance with a standard sized passenger PM shown in FIG. 12A. Thus, if the body size of the passenger seated on the seat 10 is relatively small, the following problem is caused. Specifically, if a relatively small sized passenger PS shown in FIG. 12B is seated on the seat 10, a gap is formed between the airbag 22 in the fully inflated and deployed state and the passenger PS as illustrated in the drawing. This may prevent the airbag 22 from effectively restraining the passenger PS.
In other words, the airbag may not be capable of restraining the passenger on the seat to its full performance depending on the body size of the passenger. This problem is common for all types of side airbag apparatuses.